The present invention relates to curved ultrasound transducer arrays. In particular, a curved capacitive membrane ultrasound transducer (CMUT) type of array is provided.
A curved one dimensional array of piezoelectric type elements allows scanning in sector formats. The elements of the array are separated by dicing. The resulting kerfs are filled with an epoxy or other flexible material or left empty. The flexible array of elements is bent or curved. The kerf filling material, such as epoxy, provides the flexibility for positioning the array without damage. However, piezoelectric ceramics may be expensive or difficult to manufacture and may have some undesired acoustical properties.
Another type of transducer includes one or more microelectromechanical devices (e.g., a CMUT). A flexible membrane positioned over a cavity or chamber transduces between acoustical energies through flexing of the membrane and electrical energies by variation in potential between electrodes adjacent the membrane. By providing an electrode in a chamber, variance in distance between the electrodes has a capacitive effect. The CMUT elements of one or more membranes are formed on semiconductor materials using semiconductor processes. A flat transducer array is manufactured on a silicon wafer. However, silicon wafers are generally not flexible.
Semiconductor material may be thinned or made thin enough to allow flexing of the array for a curved CMUT. However, the amount of flexing of the substrate is limited. Thinning the substrate may result in a more fragile wafer which is more likely to get damaged during manufacturing and use.